STOCKHOLM - US Secretary of State John Kerry said here on Tuesday he expected a US-Russia-backed conference to take place in early June to negotiate a peaceful transition in Syria.

"We believe the ... best way to settle Syria is through a negotiated settlement," the top US diplomat told reporters during his visit to Stockholm.

"If he decides not to come to the table, it would be another one of President Assad's gross miscalculations," he said.

"I don't believe that that is the case at this moment," he said.

The exact timing of the meeting was up to the United Nations, Kerry said.

Syria's Information Minister Omran al-Zoubi called for further details on the proposed conference before deciding whether to take part in it, state-run SANA news agency reported Tuesday.

In an interview with Lebanese al-Manar TV carried by SANA, the minister said his country would not be part of any action nor partake in any meeting that would harm the national sovereignty.

Kerry will attend a meeting of the eight-member Arctic Council in the city of Kiruna in northern Sweden on Wednesday.